Remove orphaned label links and add a foreign key constraint

Closes gitlab-ee#7482

See merge request gitlab-org/gitlab-ce!21552

Include private contributions in user contribution graph

Closes #14078

See merge request gitlab-org/gitlab-ce!17296

On GitLab.com, there are over 2 million orphaned label links out of
a total of 13 million. These orphaned label links can cause
quiet failures, such as unexpected nil values in ExportCsvWorker.

Closes gitlab-org/gitlab-ee#7482

Ask user explicitly about usage stats agreement

Closes #48962

See merge request gitlab-org/gitlab-ce!21423

Resolve "Remove old storage logic from Import/Export"

Closes #51144, #50109, #48778, and #51079

See merge request gitlab-org/gitlab-ce!21409

Resolve "Wiki page attachments not rendered properly"

Closes #51196

See merge request gitlab-org/gitlab-ce!21572

Replace whitespaces in wiki page attachments file names

Closes #51194

See merge request gitlab-org/gitlab-ce!21569

Send max_patch_bytes to Gitaly via Gitaly::CommitDiffRequest

Closes #50635

See merge request gitlab-org/gitlab-ce!21575

Use ResourceLabelEvent for tracking label changes

Closes #48483

See merge request gitlab-org/gitlab-ce!21281

Port cleanup tasks to use Gitaly

Closes #40529 and gitaly#954

See merge request gitlab-org/gitlab-ce!21588

Encode remote root ref

See merge request gitlab-org/gitlab-ce!21583

Rake tasks cleaning up the Git storage were still using direct disk
access, which won't work if these aren't attached. To mitigate a
migration issue was created.

To port gitlab:cleanup:dirs, and gitlab:cleanup:repos, a new RPC was
required, ListDirectories. This was implemented in Gitaly, through
https://gitlab.com/gitlab-org/gitaly/merge_requests/868.

To be able to use the new RPC the Gitaly server was bumped to v0.120.

This is an RPC that will not use feature gates, as this doesn't scale on
.com so there is no way to test it at scale. Futhermore, we _know_ it
doesn't scale, but this might be a useful task for smaller instances.

Lastly, the tests are slightly updated to also work when the disk isn't
attached. Eventhough this is not planned, it was very little effort and
thus I applied the boy scout rule.

Closes https://gitlab.com/gitlab-org/gitaly/issues/954
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/40529

dedupe frontend dependencies

See merge request gitlab-org/gitlab-ce!21590

Update robots.txt (#51167)

See merge request gitlab-org/gitlab-ce!21585

Improved IDE commit flow

Closes #48182

See merge request gitlab-org/gitlab-ce!21471

Check if key is present with string not symbol

Closes #51225

See merge request gitlab-org/gitlab-ce!21589

moved heights into variables

Closes #48182

don't add trailing = when in urlParamsToArray function

See merge request gitlab-org/gitlab-ce!21179

closes gitlab-org/gitlab-ce#51225

Fix NamespaceUploader.base_dir for remote uploads

See merge request gitlab-org/gitlab-ce!21308